When a vehicle is subjected to irregularities in its path, e.g., transverse joints in the road, an impulse is transmitted through the chassis to the vehicle's drive train comprised of the engine and transmission. Since for acoustical reasons, the engine is supported on the chassis, i.e., on supports in the vehicle frame or on the unit body chassis, the engine is excited and begins to vibrate at its natural resonant frequency of approximately 7-10 Hz, depending on its harmonics. This low frequency sinusoidal vibration of the engine in turn causes the associated part of the vehicle to vibrate, which is detrimental to ride comfort and is particularly disadvantageous when several transverse joints are present at a distance such as to produce, at a particular vehicle speed, the frequency which corresponds to the natural frequency of the engine or the drive train.
Efforts have been made to suppress this low frequency vibration as quickly as possible by damping. This damping can be natural damping by means of the material in rubber metal engine mounts or external damping by means of shock absorbers or a special solution in the case of hydraulic mounts. Although damping does improve low frequency vibration behavior, it simultaneously worsens high frequency or audible range vibration behavior, so that this solution, particularly in the case of four-cylinder, in-line engines, cannot always be used.